A Japanese laid-open patent application with a laid-open No. Sho 48-94429 proposed a device which automatically switches an exposure control device to a flash photography condition, determining, a condition notwithstanding the brightness level of the scene, when a difference larger than a given value exists between the brightness of a portion of a scene to be photographed such as the brightness of a main object and the average or integrated brightness of the scene or the brightness of the background.
The device disclosed in the Japanese laid-open patent application of the laid-open No. Sho 48-94429 determines a contralight condition when a difference larger than a given value exists between the brightness of a main object, and the brightness of the background. The device then fires a strobe to compensate for the difference of the brightness. However, the device is switched to a flash photography condition to effect photography with a strobe being used even when a camera shutter is released with the charging in the strobe being incomplete, i.e. before the main capacitor for energizing the flash tube is charged to a required level. If the shutter is released with the charging of the main capacitor being incomplete, the strobe is not fired or a sufficient amount of flash light emission is not provided so that a desired result is not obtained. If a release lock device is added to the above mentioned prior art device to disable the photography until the main capacitor for energizing the flash tube is charged, the the result expected from the device will be attained. However, it generally takes time for the main capacitor to be charged to a required level, and it is likely that a shutter chance is lost. Additionally, it is of no use to fire the strobe even in the contralight condition if the object to be photographed is so far away from the camera that a sufficient amount of flash light can not reach the object.